The 125% factor applicable only for continuous loads, but is a servo system a continuous load by NEC definition?
Ralph McDiarmid, AScT Compliance Engineering Group Xantrex Technology Inc From: [email protected] [mailto:[email protected]] On Behalf Of Brian O'Connell Sent: Monday, July 20, 2009 1:56 PM To: 'IEEE EMC & SAFETY PSTC' Subject: RE: NFPA 79 2007 section 19.3 - why 125% Table 13.5, Note 2 - The sources for the ampacities in this table are Table 310-16 of NFPA 70, National Electrical Code. My _conjecture_ is that it will correspond to the 25% de-rate that is used for the self-heating for several conductors in a raceway. Brian From: [email protected] [mailto:[email protected]]On Behalf Of [email protected] Sent: Monday, July 20, 2009 12:35 PM To: 'IEEE EMC & SAFETY PSTC' Subject: NFPA 79 2007 section 19.3 - why 125% Does anyone know why NFPA 79 requires servo system conductors to be sized to 125% of the [servo] equipment? What is foreseen in a servo system's current profile that warrants the extra "head room?" Regards, Lauren Crane - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
